The present invention relates to an improved stop for a drawer slide and specifically to a floating bumper for stopping and holding a drawer slide in a closed position.
Individual drawer slides consist of two or more members, a stationary member and at least one telescoping member. The stationary member is typically mounted in a cabinet or desk, while the telescoping member is typically connected to a drawer which is to be extended and retracted from the cabinet or desk. Drawer slides are typically provided in pairs, one for each side of the drawer. A three member slide has an intermediate member engaged by means of roller bearings and bearing retainers with the stationary member and the drawer member to enable longer drawer extensions.
In two member and three member slides, the members are coupled to each other by means of ball bearings. These ball bearings are preferably fitted within a channel shaped bearing retainer located between the slide members. Bearing retainers are fitted between slide members, e.g. the inner and intermediate slide member and between the intermediate and outer slide member. Each slide member also has a channel shape comprising a central web and two bent leg portions extending longitudinally along opposite sides of the central web.
When the telescoping member(s) is fully extended, the drawer is at the limit of its travel from the space within the cabinet in which it is mounted. When the drawer is fully retracted, the telescoping member encounters a rear stop. Typically, the rear stop is formed by bending a selected portion of the web of the stationary member such that it extends into the channel defined by the stationary member. The stop is thus a tab extending from the outer member into the pathway of the inner slide member, and into the pathway of the intermediate and inner slide members in a three member slide. In the usual design, a rubber bumper is force fitted over the rear stop member. In such embodiment, the rubber bumper is slotted and pushed down over the tab. Typically the slot is narrower than the width of the tab, and the bumper has to be stretched in order to fit it onto the tab putting the bumper into constant tension.
The bumper functions in the following manner. In a three member slide, when the intermediate member slides within a stationary member to its retracted position, its movement stops when the web of the intermediate member strikes the rubber bumper. The inner sliding member continues its travel until it also encounters the rubber bumper. When the inner member encounters the rubber bumper, the inner surfaces of the inner member bent leg portions, bracketing a cutout portion of the inner member web, engage and slide past the sides of the rubber bumper thereby compressing it slightly. As the inner member is slid further, a bent flange portion of the web of the inner member on the front end of the inner member also comes to a stop against a front stop. As the inner member front flange portion comes to a stop, the inner member bent rear legs move past the bumper and a slight inward cant of the bent rear legs causes the inner member to be held in place until a positive extension force is again applied to the slide. This retention action holds the drawer in a closed position until the next subsequent extension.
The constant stretching and compressing of the rubber bumper while mounted on the stop member provides fatigue and causes the elasticity of the bumper to deteriorate. Consequently, the bumper cracks and ultimately fails. Since such bumpers are located at the rear end of slide on the stationary member, changing them is a problem after being mounted in a desk or cabinet. As such, there is a need for a rubber bumper for mounting on a stop member of a slide which has an enhanced operating life.
Moreover, when in a closed position, a significant section of the inner member rear end extends beyond the interior end of the ball retainer. The longer the slide, the longer the portion of the rear end of the inner member that extends beyond the retainer when the slide is in a closed position. Consequently, as the inner members slid rearwards to close the slide, the inner member rear portion may flex or bend slightly or be out of alignment. As a result, the inner member rear web may dig into the bumper and tend to cause the bumper to disengage from the rear stop tab as the inner member is slid back further. As such, there is a need for a bumper that will not disengage from the rear stop tab when a inner member accidentally contacts it.